Accurate analogs for prostheses using computer generated anatomical models

ABSTRACT

Pre-surgical planning for cranial and facial reconstruction includes preparing a computer generated jaw or skull model for determining a locational position for a dental implant, a surgical bone implant to repair missing bone in the cranium, install ear prostheses, and/or install nose prostheses. The computer generated jaw or skull model is made from medical imagery and computer aided design. A surgical guide is prepared with oversize holes in registration with analogs for the dental or surgical bone implants to be inserted at the locational positions determined by a dentist or surgeon in the jaw or cranial skull model. The surgical guide is fitted atop each analog, and the surgical guide is bonded to the jaw or skull model at a predetermined angle of the analog in the jaw or skull. The surgical guide is removed from the model attached to the law or skull of a patient for accurate drilling during the dental or surgical procedure for insertion of the implants into the jaw or skull of the patient.

RELATED APPLICATIONS

This application is a continuation in part of application Ser. No.11/449,461, filed Jun. 8, 2006, which application is a continuation ofapplication Ser. No. 10/056,101, filed Jan. 24, 2002 and claims priorityunder 35 U.S.C. 120 therefrom, which application claims benefit under 35U.S.C. 119 (e) of provisional application Ser. No. 60/316,832 filed Aug.31, 2001 and provisional application Ser. No. 60/402,187 filed Aug. 10,2002.

FIELD OF THE INVENTION

This invention relates generally to the construction of a dental orcranial prosthesis that is attached to an implant in the bone of aperson's jaw or skull.

BACKGROUND OF THE INVENTION

Dental implants are a common treatment for the replacement of a missingtooth or missing teeth. An implant is placed into the bone in a person'sjaw in a variety of fashions and using a variety of systems. The boneand the implant adhere together in a process known as osseointegration,thus enabling a person to have a new tooth or set of teeth held intoposition in the jaw utilizing screws to hold them down.

Many firms manufacture complete systems of dental implants andprosthetic components for subsequent attachment to the implant. In atypical construction, the implant has an axially threaded hole at itstop, that is, the proximal end, near the gum surface. After the implanthas integrated with the bone, the gum of the implant is opened to exposethe tapped hole. Then a transmucosal abutment is attached to the tappedhole of the implant and extends to a level above the gum orsubstantially to the gum surface. The protruding free end of theabutment is constructed for attachment of a prosthesis. For preventingrotation of the prosthesis, the protruding end of the abutment requiresa non-round shape and a hexagon protrusion has been widely used. Arecessed hexagon is also popular with some systems. The abutment alsoincludes a central threaded hole concentric with the threaded hole ofthe implant and extending inward toward the jaw bone.

A false tooth or frame is provided with a hole therethrough, known inthe industry as a chimney, and a non-round recess in its basecorresponds in shape to the protruding non-round cross section for theabutment. Thereby, the crown can be connected to the abutment andrelative rotation between them is prevented so long as critical contoursof the abutment and the recess in the crown are maintained.

To prevent the crown or bridge from lifting axially from the abutment, afinal screw is passed into the chimney opening and engages the tappedhole in the implant by way of the abutment so as to hold the crownaxially to the abutment and to the implant. Thus, the crown cannotrotate about the abutment or implant because it is mated with thespecial contours on the exposed end of the abutment. The abutment issimilarly mated to the proximal or outer end of the implant. The crowncannot pull away from the abutment when the screw has been tightenedinto place.

Finally, the chimney above the screw is filled with a composite materialthat hardens and is shaped as part of the crown to look lie a naturaltooth.

There are many variations in construction.

In an alternative method, the crown is attached directly to a non-roundprotrusion of the implant and is held directly to the implant by a goldscrew without use of an intermediate abutment.

The implant is intended to be a permanent fixture in the jaw bone. Theabutment and crown may be replaced if necessary due to damage or poorfit by gaining access to the screw head by way of the chimney, andbacking off the screw so that the crown and abutment or crown to theimplant can be separated from the implant. Thus repairs may be made ofan abutment and crown with no or little inconvenience.

Therefore, the fit of an implant with the crown or frame must beperfect. If a prosthesis is placed into the mouth and does not seatcorrectly, the implant or abutment can be damaged. If an implant isdamaged there are not many options for its repair. In cases where therehave been a poor fit, the screws have broken inside the abutmentrequiring the replacement of the abutment. There have been cases wherethe screw broke inside the implant. The implants cannot be replacedwithout surgically removing them. Placing a new implant in the same spotis not an advised option.

Among related patents disclosing dental analogs include U.S. Pat. No.6,142,782 of Lazarof, which shows a dental analog with annular wings.However, the annular wings do not hinder rotating and thereforemisplacement of the analog within the replica cast stone. The annularwings of Lazarof do not intersect with the cast stone material enough toprevent rotation.

An alternative method for making dental prostheses that does not involvemaking an impression of the patient's mouth has been recentlyintroduced. It is based on Solid Freeform Fabrication (SFF) which is anindustrial prototyping technique whereby 3-D Computer Aided Design (CAD)files describing a part are used to guide the actual fabrication of asolid object by one of a variety of additive methods such asstereolithography, laminated object manufacturing, or fused depositionmodelling. U.S. Pat. No. 6,978,188 of Christensen as well as hispublished patent application 2005/0133955 illustrate how CT scans or MRIscans can be substituted for CAD input to create the files necessary todrive a stereolithography system which can then be used to model humanbone features. Medical Modeling LLC has used such a method in theirAccuDental (TM) system to create dental prostheses. Prior toimplantation of posts, a scan is made of a patient's jaw. This data isused to create files resulting in an accurate solid translucent resinmodel of a patient's jaw. Teeth and roots are rendered in a differenthue to show clearly how the teeth are anchored in the jaw bone. A dentalsurgeon then indicates on the jaw model where analogs are to be placedin the model and at what angle they should be inserted. Holes are thendrilled into the jaw model to accept the analogs. A surgical guide isthermally formed on top of the implant region of the model engaging theteeth or ridge surface with a close fit and transferring the analogpositions accurately. Alternatively, computer generated surgical guideswhich fit onto a jaw model are used. Surgical guide sleeves at theappropriate angle are then bonded at the analog sites onto the surgicalguide. The surgical guide is snapped off the teeth or ridge surface ofthe model and will be transferred to the patient's mouth and snappedonto the actual teeth or the ridge surface thereby providing accurateguides for drilling the holes for the actual implants while at a remotelab, the prosthesis is being fabricated using the analogs in the jawmodel. Surgical guides fit not only on teeth, but can be used on totallyedentulous jaws as well engaging soft tissue or bone surface asrepresented on the jaw model and on the actual patient jaw.

OBJECTS OF THE INVENTION

Accordingly, it is the object of the invention to provide a method forinsuring the most accurate seating possible of a prosthesis to anabutment or implant in the jaw or skull of a patient.

SUMMARY OF THE INVENTION

The present invention comprises an implant analog that may include astandard abutment that can be mounted in the dental lab replica of therelevant section of a patient's mouth more securely than heretoforepossible. Because of the inventive implant analog, dental labs can nowcreate a crown that will attach more accurately to the implant in thepatient's mouth. The analogs of the present invention are desirablylonger than the analogs used heretofore and have a pin that projectsfrom the base of the analog. Desirably, the inventive analogs have aside ridge. Moreover, the analog has substantially the same height anddimensions as a conventional implant and abutment. In a preferredembodiment, the analog of the present invention is formed from stainlesssteel.

A careful confidential experiment was conducted at New York Universityof School of Dental Medicine by Dr. C. Jager, Dr. G. R. Goldstein, Dr.E. Hittelman and the Applicant herein. The experiment was designed tocompare the performance of a prior art analog of NOBEL BIOCARE®, asshown in FIG. 9, to that of one embodiment of the present invention, asshown in FIG. 4. A statistically significant improvement for the presentinvention was found in terms of framework fit. Also, resistance toapplied torque was found to be significantly improved for the analog ofthis invention.

The experiment evaluated torque prostheses to laboratory dental implantanalogs. The study evaluated the movement of the prior art analog ofNOBEL BIOCARE®, as shown in FIG. 9, and the embodiment shown in FIG. 4of the present invention. Both were torqued to 20 Ncm in a reinforcedtype IV die stone. 80 analogs were divided into groups of 4 analogs,including three of the prior art analog shown in FIG. 9 with one of thepresent invention shown in FIG. 4. These analogs were embedded in thirtyequal blocks of Type IV plaster stone using a prefabricated four unitimplant framework. Of the twenty analogs, ten were imbedded in the stoneat a depth of four cm and ten were imbedded at a depth of six cm fromthe implant platform. These groups of ten were then divided into groupsof five each, where five of the prior art analogs shown of the presentinvention in FIG. 9 were torqued to 20 Ncm in each group and fiveanalogs shown in FIG. 4 were torqued to 20 Ncm. The initial frameworkwas used to evaluate the fit of each analog therein. In the 4 mm depthgroup of the prior art shown in FIG. 9, two of the five samples (40%)did not allow the framework to fit the analog. In the 6 mm depth of theprior art analogs shown in FIG. 9, three of the five samples (60%) didnot allow the framework to fit. However, all of the dental analogs shownin FIG. 4 of the present invention fit back to the cast.

As a result, the analogs of the present invention, as shown in FIG. 4,were able to resist movement within a stone cast when torqued, unlike asignificant portion of the prior art dental analogs shown in FIG. 9.

Therefore, the dental analogs of the present invention have unexpected,beneficial results not achievable with the dental analogs of the priorart shown in FIG. 9.

A method of preparing dental crowns efficiently and accurately, includesthe steps of:

-   -   a. preparing an analog for a jaw implant supporting a dental        crown mounting pin having at least one anti-rotation anchoring        projection extending discretely and radially from said pin        adjacent a bottom end thereof;    -   b. inserting bottom-end-down said prepared mounting pin into a        dental crown casting mold;    -   c. securing said prepared mounting pin temporarily in place        within said casting mold;    -   d. adding settable plaster or plastic molding material to said        casting mold so as to embed said bottom end of said pin by        surrounding said bottom end of said pin with said plaster or        plastic molding material;

e. allowing said plastic molding material to set and harden with saidprepared pin embedded within said molding material; and

f. utilizing said embedded mounting pin to make a dental crown.

Regarding the alternative method described in the previous section usinga resin model of a patient's jaw, the analogs used must be resistant topull-out and rotation as in the method using the stone plaster method.Whether the resin model is a product of stereolithography or otherwisefabricated, it is drilled to accept an analog post. The alternateembodiment of this invention describes analog posts with features forrobustly grasping the side walls of these retaining holes in the resinmodel. Clearly, transverse or radially protruding features cannot beappended to the analog posts since these would not be compatible withinsertion.

The first alternate embodiment uses a single axially attached rod orwing on the lower portion of the analog post. The post is then forcedinto a slightly undersized hole and resists both twisting and pull-out.A second embodiment using axial rod features uses two such rods onopposite sides of the analog post. A third such embodiment uses threesuch rods attached every 120 degrees around the bottom end of the post.Any number of such rods can be attached preferably in a symmetric array.The rods can also be enhanced in their gripping action by texturizingtheir outer surface; alternatively, axial grooves along their length attheir outermost position can be added.

Another embodiment of analog post for hole engagement is made of alarger diameter with a tapered top; a regular array of longitudinalgrooves or flutes on the outer side surface engage the hole sides. Yetanother embodiment of analog post is one with a knurled outer surfaceand an annular groove near the bottom end. A final embodiment has malethreads along the analog shank which permit screwing into the hole inthe resin model much akin to the thread-forming action of a wood screwin a pilot hole in wood.

When using model based presurgical planning techniques, computer basedstereolithography or non-computer methods are used to create an accuratejaw model of resin, plaster, or “stone” or other plastic material.Similarly, surgical guides which form fit onto the jaw model and ontothe patient's jaw are also created. Once analogs are inserted into thejaw model, surgical guide sleeves are bonded to the surgical guide atthe analog sites using cement or adhesive inside oversized holes in thesurgical guide. These must be at the appropriate height, and theorientation must match that of the analogs in the jaw model. Anotherembodiment of this invention is a set of accessory parts and a method toinsure that the alignment of the surgical guide sleeves bonded to thesurgical guide will match that of the analog in registration.

After the analogs are inserted in the jaw model, at each analog siteattachments to each analog are made which will orient the surgical guidesleeve rigidly and accurately to represent the orientation of theanalog. After all the surgical guide sleeves are thereby attached to theanalogs, the surgical guide with oversize holes at each analog site islowered onto the jaw model and all surgical guide sleeves are bonded tothe surgical guide while they are still attached to the analogs. Afterthe cement or adhesive sets, screws are removed from each analog to freethe surgical guide with all of the surgical guide sleeves accuratelyattached. The guide is then used inside the patient's mouth to drillaccurate implant holes by using each of the surgical guide sleeves asdrill guides.

The parts attached to each analog in the jaw model are a surgical guidesleeve supported by a form-fitting cylinder support mount, a tubeadapter to adjust the height of the guide sleeve above the analog (ifnecessary), and a screw threaded through the three parts from the top tosecure the assembly to the analog below.

Presurgical planning techniques using accurate whole skull models ormodels of skull portions other than jaws are also used for cranial andfacial reconstruction. Attachments use surgical implants in bone. Forexample such an approach is used to repair missing bone in the cranium,ear prostheses, and nose prostheses. The procedure starts with anaccurate model and a surgical guide with oversize holes in registrationwith the analogs inserted at sites determined by a surgeon on the skullmodel. Using the procedure and analog attachments as described above fordental implants, appropriately sized tube adapters, cylinder supportmount, surgical guide sleeve and attachment screw are attached to eachanalog in the skull model. The surgical guide is then fitted carefullyatop the protruding elements atop each analog, and the surgical guidesleeves are cemented or otherwise bonded within the oversize holes ofthe guide capturing the precise angle of the analog in the model. Theanalog screws are then removed releasing the surgical guide with guidesleeves attached for accurate drilling during the surgical procedure forinsertion of the implants.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can best be understood in connection with theaccompanying drawings. It is noted that the invention is not limited tothe precise embodiments shown in drawings, in which:

FIG. 1 is a view of a dental lab replica showing the position of ananalog and an abutment;

FIG. 2 is a view of a lower jaw about to receive a prosthesis and havingtwo implants;

FIG. 3 is a view of an embodiment of the present invention incorporatinga conical abutment;

FIG. 3A is a partial view taken within the phantom circle of FIG. 3,shown rotated ninety degrees for clarity;

FIG. 4 is a view of an embodiment of the present invention incorporatinga standard abutment;

FIG. 5 is a view of an embodiment of the present invention correspondingto an implant with a hexagonal protrusion;

FIG. 6 is a view of an embodiment of the present invention correspondingto a large diameter implant with a hexagonal recess;

FIG. 7 is a side elevation view in partial cross section of anembodiment of the present invention corresponding to an implant with ahexagonal recess;

FIG. 7A is a top plan view thereof;

FIG. 8 shows a conventional impression coping with depth indicationsfrom 2-5 mm;

FIG. 9 shows a conventional prior art fixture replica, or analog, whichis replaced by analog according to the present invention;

FIG. 10 shows the placement of a fixture replica, either a conventionalor according to the present invention, in the lab replica that is to besecured to an abutment and a crown via a guide pin;

FIG. 11 shows the attachment of a fixture replica, either a conventionalor according to the present invention, to an impression coping that isfixed in an impression of the relevant section of a patient's mouthprior to the casting of the lab replica;

FIG. 12 shows a dental impression tray modified to provide access to theimpression coping that is secured to the implant in a patient's mouth bya guide pin;

FIG. 13 shows the excess material around the impression coping in a traycontaining impression material, the impression coping being secured tothe implant in the patient's mouth by a guide pin;

FIG. 14 shows a means of securing the impression coping to the traycontaining the impression material with an acrylic resin;

FIG. 15 shows the impression containing the impression coping;

FIG. 16 is a top view of an engagement plate of this invention which isused to provide improved anchorage for a conventional analog;

FIG. 17 is an exploded side view of the engagement plate of FIG. 16attached to a conventional analog;

FIG. 18 is a perspective view of an analog body with a transverse tubeconfigured to screw into a variety of abutments;

FIG. 19 is a perspective view of an analog body with transverse wings;

FIG. 20 is a bottom view of an analog body with transverse wings;

FIG. 21 is a perspective view of an analog body with coplanar transversetubes at right angles;

FIG. 22 is a perspective view of an analog body with non-coplanaroblique tubes;

FIG. 23 is a bottom view of an analog body with eight co-planartransverse tube segments;

FIG. 24 is a perspective view of an analog body with angled spikes;

FIG. 25 is a side elevation of an analog body with serrated sideextensions;

FIG. 26 is a side elevation of an analog body with four serrated andperforated side extensions;

FIG. 27 is a perspective view of an analog body with looped sideextensions;

FIG. 28 depicts a cross-sectional view of a protrusion in an analoghaving a substantially oval shape 2802;

FIG. 29 depicts a cross-sectional view of a protrusion in an analoghaving a substantially triangular shape;

FIG. 30 depicts a cross-sectional view of a protrusion in an analoghaving a substantially square shape;

FIG. 31 depicts a cross-sectional view of a protrusion in an analoghaving a substantially rectangular shape; and,

FIG. 32 depicts a cross-sectional view of a protrusion in an analoghaving a substantially hexagonal shape 3202.

FIG. 33 is a (prior art) perspective view of a plastic resin jaw modeland a surgical guide illustrating the relation between the two.

FIG. 34 is a (prior art) perspective view of a resin jaw model withanalog posts installed.

FIG. 35 is a perspective view of an analog post of this invention with asingle side rod or wing attached.

FIG. 36 is a perspective view of an analog post with two axial wings.

FIG. 37 is a top plan view of an analog post with three symmetricallyattached side rods or wings.

FIG. 38 is a side elevation detail showing texturing on the side of arod or wing.

FIG. 39 is a perspective detail of showing a longitudinal groove on theside of a rod.

FIG. 40 is a perspective view of a fluted analog post.

FIG. 41 is a perspective view of a knurled analog post with an annulargroove adjacent the bottom end.

FIG. 42 is a side elevation of an analog post with male thread on itsshank surface.

FIG. 43 is a perspective view of a cylinder sleeve support mount.

FIG. 44 is a side crossection of the mount of FIG. 43.

FIG. 45 is a side crossection of the cylinder sleeve support mountinside a surgical guide sleeve to show the fit of the two parts.

FIG. 46 is a side elevation of a retaining shoulder screw.

FIG. 47 is a perspective view of a short tube adapter.

FIG. 48 is a perspective view of a medium height tube adapter.

FIG. 49 is a perspective view of a larger diameter and taller tubeadapter.

FIG. 50 is a side exploded view of the five parts from top screw tobottom analog.

FIG. 51 is a side detail crossection of two assemblies attached to twoanalogs in a jaw model with a section of surgical guide in registrationwith the two analogs but spaced apart for clarity.

FIG. 52 is a perspective view of an accurate skull model showing analogsinserted for cranial repair, ear prosthesis, and nose prosthesis withaccurate surgical guide for the cranial repair.

DETAILED DESCRIPTION OF THE INVENTION

Simplified, the construction of the prosthesis begins after theosseointegration of the implant with the dentist making an impression ofthe relevant section of the patient's mouth. When constructing theprosthesis, the dentist makes an impression including an impressioncoping. Desirably, the impression material employed is hard and elasticwhen set, such as the materials sold under the trade names IMPRAGUM,EXPRESS and PRESIDENT.

Once the impression material hardens, the tray containing the impressionis sent to a dental lab where the prosthesis is made. The dental labuses this impression to make a replica of the relevant section of thepatient's mouth. Typically, the replica is made of gypsum to formplaster, and is made to reproduce the milieu into which the prosthesisis to fit, including, for example, any hexagonal protrusion or recessionin the abutment the dentist is using. Alternately, the replica can alsobe made of plastic, such as resin.

For example, FIG. 1 shows a view of dental lab replica 130 with analog120 and abutment 110.

Moreover, FIG. 2 shows an actual patient lower jaw with two implants220, a three tooth prosthesis 210 and screws 230 to retain prosthesis210 in implants 220.

In making the impression, the impression coping is attached to theimplant in the same way the final prosthesis will attach. The impressioncoping rests flush on top of the implant, or implant and abutment, witha guide screw passing through and into the implant. The impressioncoping remains in the impression in the same position that was in themouth and the guide screw must be removed before the impression can beremoved from the patient's mouth.

In making the dental lab jaw model, or replica, the analog is attachedto the impression coping with a guide screw going through the impressioncoping and into the analog. All of the teeth in the relevant portion ofthe mouth are replicated in the model, which desirably is made ofgypsum. The goal is to have the analog in the replica in the positionthat corresponds to the position of the implant in the patient's mouth,including the orientation of any protrusion or recess.

The present day tools offered by the implant manufacturers utilize brassor stainless steel analog.

The configuration of the prior art analogs replicates the internalthread dimension of the implant or abutment and copies the shape of theexternal or internal hexagon. However, the outside diameter of a priorart analog maintains a shape that is not consistent with the needs ofthe dentist or technician in constructing the prosthesis. Conventionalanalogs are too small and are removed from the gypsum model too easily.Moreover, the exterior surface of conventional analogs are too smoothwhich permits the analog, and thus the prosthesis, to rotate in themodel during construction of the prosthesis. Such rotation moves thehexagonal position of the prosthesis into a position that does not matchthe corresponding position of the implant in the patient's mouth.

In contrast to the prior art conventional, easily rotatable anddislodgable dental analogs, the present invention is a new analog thatwill not allow any rotation in the gypsum model. In a preferredembodiment, as shown in FIGS. 3 and 3A, the analog 320 of the presentinvention is substantially longer and has a unique feature of atransverse pin 312 or other protruding geometric shaped member extendingthrough hole 314 in its side.

FIG. 4 shows analog 420 with abutment 22 and hole 414 for insertion of apin therein, similar to pin 312 of FIG. 3A.

As shown in FIGS. 5, 6, and 7, these dental analogs 520, 620 and 720 ofthe present invention are preferably ridged with annular recesses, thesedental analogs 520, 620 and 720 on their respective sides to gain betterretention inside the gypsum model.

Analogs 420, 520, 620 and 720 have respective pins (not shown) similarto transverse pin 312 of analog 320 of FIG. 3A. These pins 312 arelocated at the base of the respective analogs 320,420, 520, 620 and 720to lock the position. These transverse pins 312 prevent horizontal,vertical or cylindrical movement of the analogs 320, 420, 520, 620, and720 within the model.

Conventional implants have a standardized system of heights,measurements and dimension for implants and abutments. The respectiveinventive analogs 320, 420, 520, 620, 720 of the present invention canhave a shape which incorporates a conical abutment 322 (FIGS. 3 and 3A),a standard abutment 422 (FIG. 4), a hexagonal protrusion 522 (FIG. 5), alarge hexagonal recess 622 (FIG. 6) or a hexagonal recess 722 (FIG. 7),as these terms are used in the dental industry. For example, FIGS. 28-32depict cross-sectional views of protrusion embodiments having variousshapes. Illustratively, FIGS. 28-32 are described with respect toprotrusion 2012 however that description is not intended in any way tolimit the scope of the invention. For example, it is appreciated thatextensions 2051 may in various other embodiments have the shapesdepicted in FIGS. 28-32. FIG. 28 depicts a cross-sectional view ofprotrusion 2012 having a substantially oval shape 2802. FIG. 29 depictsa cross-sectional view of protrusion 2012 having a substantiallytriangular shape 2902. FIG. 30 depicts a cross-sectional view ofprotrusion 2012 having a substantially square shape 3002. FIG. 31depicts a cross-sectional view of protrusion 2012 having a substantiallyrectangular shape 3102. FIG. 32 depicts a cross-sectional view ofprotrusion 2012 having a substantially hexagonal shape 3202.

Analogs 520, 620 and 720 also bear annular grooves 516, 616 and 716.

The analogs 320, 420, 520, 620 and 720 of the present invention aremachined to specified mechanical tolerances. In particular, the internalthread of the inventive analogs are closer to the threads of actualimplants and abutment. This closer approximation to the actual implantsinsures that the guide screw goes into the implant the same number ofturns the guide screw goes into the analog, and maintains the prosthesisin the same position relative to the patient's mouth as the prosthesishad with respect to the replica. The internal or external hexagon isalso closer in dimensions to the actual implant. As a result, theprosthesis will fit on the analog and on the actual implant or abutmentin the manner intended.

Another complication in the construction of dental analogs is that it isoften necessary to construct a large frame using soldered connections.The present methods of soldering require a duplicate model of high heattolerance gypsum investment be made with the present day analogs. Theframe is soldered on that model. The success rate of these solderconnections is far lower than expected in the industry. The presentinvention allows a more accurate solder connection. The presentinvention also holds better in the invested model and keeps the analogsfrom moving in the model.

EXAMPLE

In the single tooth prosthetic work, the impression is taken from thefixture level. As shown in FIG. 8, one type of conventional impressioncoping 800 has an internal hexagon at the base, which corresponds to thehexagon of the abutment. The coping has depth indications for assessmentof proper abutment size, 2 mm, 3 mm, 4 mm, and 5 mm. The upper margin ofthe abutment-like part indicates 6 mm. The impression coping istypically made of titanium.

The impression coping is used together with a special guide pin (e.g., aDCA 098), 850, for a single tooth (the guide pin used to secure theprosthesis to the implant typically has a different thread).

Typically, in the laboratory, any undercuts of the impression coping areblocked out before pouring the impression (including the depthindications). This blocking is especially important when the longestabutment is used. This precaution prevents fracturing the cast whenseparating the model and the impression coping.

During the Laboratory procedure, an analog, for example a conventionalprior art analog 900 shown in FIG. 9, or an analog of the presentinvention such as the analogs of FIGS. 3-7, is used in the laboratoryjaw model, or replica, to represent the implant in the working cast.This is illustrated in FIG. 10 where analog 1000 is set in thelaboratory jaw model, or replica, 1010, and the abutment 1020 and crown1030 are secured to the jaw model by guide pin 1040. The analog has thesame top hexagon and internal thread as the implant. In contrast to thestainless steel analogs of the present invention, conventionally,analogs were typically made of nickel-plated brass.

FIG. 11 shows an impression 1100 containing an impression coping 800being attached to an analog 1000 via guide pin 1040. Once the analog1000 is secured to the impression coping 800 by the guide pin 1040, theimpression 1100 is used to cast he laboratory jaw model, or replica,from stone, such as gypsum.

The impression 1100 containing the impression coping 800 can be preparedin any conventional manner. For example, as shown in FIG. 12, one canmake a hole 1200 in an acrylic-resin stock tray 1210 for access to theimpression coping 800 which is secured to the implant by the guidescrew.

FIG. 13 shows tray 1210 loaded with an impression material of choice1300 in the mouth with impression coping 800 secured to implant 120within the patient's jaw 1310.

FIG. 13 also shows the removal of any excess material around impressioncoping 800 once impression material 1300 has set.

Impression coping 800 is then secured to tray 1210 withauto-polymerizing acrylic resin 1400. The orientation of the hexagonalhead of the implant 120 should be maintained when the impression 1100 isremoved. Next, guide pin 850 is unscrewed and impression 1100 iscarefully removed form the patient's mouth.

As noted before, FIGS. 3-7 show different embodiments of the dentalanalogs 320, 420, 520, 620 and 720 of the present invention each using atransverse rod pin 312 or tube within hole 314, 414, 514, 614, or 714,in the base section of each analog 320, 420, 520, 620, or 720 to enhancethe anchoring of the analog in the plaster of the replica. Each of thedifferent embodiments uses a different style of abutment 322, 422, 522,622, or 722 to match that which the dentist had used in the patient'sactual implant.

For example, FIG. 3 shows a conical abutment 322 for analog rod 320 andFIG. 4 shows a standard recessed abutment 422 for analog rod 420. FIG. 5shows an abutment 522 with a hexagonal protrusion for analog rod 520,FIG. 6 shows a large diameter abutment 622 with a hexagonal recess, foranalog rod 620, and FIG. 7 shows an abutment 722 with a hexagonal recessfor analog rod 720.

FIG. 16 shows another embodiment of this invention in the form of a flatengagement plate 2000 which is used to provide enhanced anchoring of astandard prior art analog 900 (see FIG. 9) in the replica plaster.

As shown in FIG. 17, the conventional analog 2003 is inserted throughcentral hole 2001 and adhesively bonded 2004 at an oblique angle.Perforations 2002 enhance adhesion to immobilize plate 2000 in replicaplaster. An optional hollow sleeve 2005 can be used to extend thevertical height of analog 2003, to further promote its anchoring withinthe replica plaster.

It is further noted that optional removable hollow sleeve 2005 can alsohave any of the protrusions shown in the other drawing figures, such asprotrusion rods 2012 of FIG. 18 or FIG. 21, protrusion 2022 of FIG. 19,protrusion wings 2030 of FIG. 23, protrusion barbs 2032, protrusionwings 2035 of FIG. 25, protrusion wings 2040 of FIG. 26 or protrudingloops 2051 of FIG. 27.

FIG. 18 shows the concept for a series of additional embodiments ofanalogs of this invention which use a tubular body 2010 with externalthreads 2011 at the top end. These threads screw into mating femalethreads on a series of abutments 2013 (here illustrated as a conicalabutment) which are supplied to match the style and size actuallyimplanted in the patient's jaw.

Therefore, analogs of this general category of embodiments can bematched with a variety of abutments 322, 422, 522, 622, or 722 (asdescribed in FIGS. 3-7). The analog 2010 with conical abutment 2013 ofFIG. 18, similar to analog 320 with a conical abutment 322, uses atransverse tube or rod 2012 to aid in anchoring body 2010 in plaster.Slotted body 2020 as shown in FIG. 19 accepts two rectangular wings 2021(as shown in bottom view of FIG. 20) with perforations 2022 as yetanother embodiment to resist rotation within, and extraction from, thereplica plaster.

The embodiment shown in FIG. 21 uses coplanar radial transverse tubes2012 at right angles to each other to provide anchorage.

The embodiment shown in FIG. 22 uses two oblique tubes 2012 whichpenetrate body 2010 as anchorage.

The bottom view of the embodiment of FIG. 23 shows eight equally spacedtubular segments 2030 attached to body 2010 to provide anchorage inreplica plaster.

FIG. 24 shows an embodiment of an analog using tubular body 2031 withupward angled spikes 2032 in two rows to provide anchorage.

The embodiment of FIG. 25 shows slotted body 2020 with a pair ofserrated triangular wings 2035 to provide anchorage in the replicaplaster.

FIG. 26 shows an embodiment of an analog with body 2039 with four slotsaccommodating four perforated and serrated triangular wings 2040 torigidly anchor it to the plaster of a replica.

Furthermore, FIG. 27 shows an embodiment of an analog using tubular body2050 with one or more outwardly extending looped extensions 2051 topromote anchorage.

FIG. 33 illustrates some features of the alternate method incorporatinga resin jaw model to fabricate a prosthesis. Resin jaw model 4000 istranslucent and shows teeth in a contrasting hue in the jaw. Marks 4001placed by a dental surgeon indicate the location for the center of eachanalog hole to be drilled. Marks 4002 illustrate the proper angle forsuch analog retaining holes. Surgical guide 4010 is shown “popped-off”the teeth of jaw model 4000 over which it is formed by a thermalprocess. Surgical guide sleeves 4011 are shown attached at the properangles to drill the implant post holes in the patient's jaw. Threeanalog posts 4020 are shown installed in jaw model 4000 in FIG. 34.

The analog posts in FIGS. 35-42 all have features to resist pull-out androtation when installed in holes of a resin jaw model. FIG. 35 showsanalog post 4030 with one side rod or wing 4032. FIG. 36 shows analogpost 4035 with two wings 4032 attached to opposite sides of post shank4031. FIG. 37 shows a symmetric attachment of three side wings 4032 froma top view. In all cases, these analog posts are forced inside a holeslightly smaller than would normally accommodate an analog shank withits side wings. The wings will embed into the sides of the retainingholes. FIG. 38 shows texturing 4046 as applied to outer edge of sidewing 4032 to aid in retention. FIG. 39 shows groove 4051 along thelength of side wing 4032 which can be used for the same purposealternatively.

In lieu of side wings or attached rods, FIG. 40 shows fluted analog post4055 with longitudinal grooves 4057 and a tapered top end 4056 whichwould be below the top surface of the retaining hole. FIG. 41illustrates yet another embodiment of analog post 4060 which is knurled4061 along its entire outer shank. An annular groove 4062 also enhancespull-out resistance. The analog post 4065 of FIG. 42 is screwed into ananalog hole via tapered bottom 4066 and thread-forming male threads 4067along its shank.

FIGS. 43-51 illustrate a presurgical method for aligning surgical guidesleeves in a surgical guide so they can be bonded in the properorientation for use in a patient's mouth to accurately drill holes foraccepting implant posts. Three parts are used for this. FIG. 43 shows acylinder sleeve support mount 4080 with center hole 4083, shank 4082 andflange 4081. FIG. 44 shows the key dimensions of the various parts whileFIG. 45 shows the fit of support mount 4080 within surgical guide sleeve4011. The O.D. of flange 4081 (DD) matches the O.D. of guide sleeve4011. Shank 4082 of diameter D fits in a close clearance fit insideguide sleeve 4011 which is slightly longer (LL) than height dimension L.This is to insure rigid locking by shoulder screw 4090 of FIG. 46 whichhas a head 4091 also of dimension DD; threads 4093 engage the centralthreaded hole of an analog. Note that shoulder 4092 diameter dl isslightly smaller (close clearance fit) than hole of diameter d insupport mount 4080. FIGS. 47-49 illustrate three different heights h1,h2, and h3 of tube adapters 4100, 4110, and 4120 respectively whichmatch the outside diameter (O.D.) of an analog. Analog 4120 would beused with a larger diameter analog. Many such adapters would be madeavailable to adjust the height of the surgical guide sleeve above thetop of an analog as required. FIG. 50 shows an exploded view of theassembly of the five parts. Although analog 4065 of the screw-in varietyis shown, any analog would usable with this method. Referring to FIG.51, side crossection detail 4150 of the jaw model shows two analogs, one4065 screw type and one knurled type 4060, rigidly installed. The methodrequires that the progression of parts as shown in FIG. 50 is assembledand accurately and rigidly held in place by tightening screw 4090 ineach analog beneath. Note that analog 4065 has short tube adapter 4100atop while analog 4060 uses a taller 4110 adapter. In FIG. 51, theflange portion of each cylinder sleeve support mount 4080 is visibleatop the tube adapter while surgical sleeve guide 4011 is captured andguided between the head 4091 of screw 4090 and flange 4081 of mounts4080. Note also that analogs 4065 and 4060 are tilted away from eachother (not aligned) as required by the desired positioning in the jawmodel. A section of surgical guide 4160 is shown above jaw model 4150with oversize holes 4161 in registration with analogs 4065 and 4060.After the surgical guide 4160 is carefully aligned with jaw model 4150,surgical sleeve guides 4011 will be within holes 4161 where they will bebonded to surgical guide 4160. After the adhesive or cement cures,screws 4090 will be removed thereby releasing surgical guide 4160 fromjaw model 4150 with surgical sleeve guides accurately attached. Analogs4065 and 4060 will then be used by the dental lab for fabrication ofappropriate prostheses. When the prostheses are made (or before),surgical guide 4160 is returned to the dental surgeon. It is used toaccurately drill implant post holes in the patient's jaw using thesurgical sleeve guides as drill guides to replicate the orientation ofthe analogs in the jaw model for a close fit of the prostheses.

FIG. 52 shows a skull model 4200 which is typically created usingstereolithography. Analog group 4215 (8 analogs) placed around cranialinjury area 4210 will be used to plan the surgery. Also shown are agroup of five analogs 4240 which will be used to attach an earprosthesis, and a pair of analogs 4260 for a nose prosthesis. All threesites will also require accurate surgical guides for these procedures.One of these, 4220 for the cranial repair, is shown in the figure. Notethe oversize holes 4215 in registration with the array of analogs 4215.Two exemplary surgical guide sleeves 4227 are shown indicating that atotal of 8 such sleeves will have to be accurately bonded inside holes4225. To facilitate this step, the parts shown in FIG. 50, namely tubeadapter 4100, support mount 4080, surgical guide sleeve 4011 (4227 inFIG. 52), and screw 4090, are assembled in the order shown atop eachanalog 4215. Then surgical guide 4220 is placed accurately over therepair area 4210 with guide sleeves 4227 inside holes 4225. Sleeves 4227are then bonded to guide 4220. All screws 4090 are then removed therebyreleasing surgical guide 4220 with accurately bonded guide sleeves 4227;the guide sleeves will be used for drilling holes for the actualimplants in the surgical procedure. Surgical guides for the ear and noseprostheses (not shown) would be similarly prepared.

In the foregoing description, certain terms and visual depictions areused to illustrate the preferred embodiment. However, no unnecessarylimitations are to be construed by the terms used or illustrationsdepicted, beyond what is shown in the prior art, since the terms andillustrations are exemplary only, and are not meant to limit the scopeof the present invention.

It is further known that other modifications may be made to the presentinvention without departing from the scope of the invention, as noted inthe appended Claims.

1. An anchored anti-rotation analog post for preparing a dental crown for insertion into the mouth of patient, said analog post comprising: an elongated pin having opposite top and bottom ends; said pin having at least one anti-rotation anchoring projection extending discretely and radially from said pin adjacent said bottom end thereof; said at least one anchoring projection comprising a fixed wing along an outer surface of said pin and extending up from the bottom end of said pin.
 2. The analog post of claim 1 wherein said fixed wing comprises a rod extending less that a full length of said pin.
 3. The analog post of claim 2 in which said rod is textured on an outer surface thereof.
 4. The analog post of claim 2 in which said rod has an axially extending groove in an outer surface thereof.
 5. The analog post of claim 1 wherein said pin has a pair of wings on opposite sides of said pin.
 6. The analog post of claim 1 wherein said pin has multiple wings spaced along and around the outer surface of said pin.
 7. The analog post of claim 6 wherein said wings comprise rods extending less that a full length of said pin.
 8. A method of preparing dental crowns efficiently and accurately, comprising the steps of: a. preparing an analog for a jaw implant supporting a dental crown mounting pin having at least one anti-rotation anchoring projection extending discretely and radially from said pin adjacent a bottom end thereof; b. inserting bottom-end-down said prepared mounting pin into a dental crown casting mold; c. securing said prepared mounting pin temporarily in place within said casting mold; d. adding settable plastic molding material to said casting mold so as to embed said bottom end of said pin by surrounding said bottom end of said pin with said plastic molding material; e. allowing said plastic molding material to set and harden with said prepared pin embedded within said molding material; and f. utilizing said embedded mounting pin to make a dental crown.
 9. The method of claim 8 wherein said fixed wing comprises a rod extending less that a full length of said pin.
 10. The method of claim 9 in which said rod is textured on an outer surface thereof.
 11. The method of claim 9 in which said rod has an axially extending groove in an outer surface thereof.
 12. The method of claim 8 wherein said pin has a pair of wings on opposite sides of said pin.
 13. The method of claim 8 wherein said pin has multiple wings spaced along and around the outer surface of said pin.
 14. The method of claim 13 wherein said wings comprise rods extending less that a full length of said pin.
 15. A method of preparing dental prosthesis efficiently and accurately using digital and CT Scan imagery to produce a computer generated resin model of a patient's jaw, wherein the improvement comprises the steps of: a. determining a location and position and angle orientation of at least one implant post in a patient's jaw by utilizing the computer generated resin model; b. marking said locational position and orienting angle at an edge surface of the stereolithographic resin model; c. drilling a hole at said marked locational position at said orientation angle into the computer generated resin model of the patient's jaw; d. preparing an anchored anti-rotation analog post for a dental prosthesis for insertion into the mouth of patient, said analog post comprising: an elongated pin having opposite top and bottom ends; said pin having at least one anti-rotation anchoring projection extending discretely and radially from said pin adjacent said bottom end thereof; said at least one anchoring projection comprising a fixed wing along an outer surface of said pin and extending up from the bottom end of said pin. e. inserting said anti-rotation analog post into the drilled hole of the computer generated resin model of the patient's jaw; f. forming a surgical guide over said hole, wherein said surgical guide includes a computer conforming to the teeth and outer jaw surface of a portion of the jaw for accepting the implant post; g. drilling holes in the surgical guide conforming to the predetermined location and angle orientation of the implant, and h. placing the surgical guide in the patient's mouth and drilling holes for acceptance of the implant in the patient's jaw.
 16. The method of preparing dental prostheses of claim 15 wherein said fixed wing comprises a rod extending less that a full length of said pin.
 17. The method of preparing dental prostheses of claim 16 in which said rod is textured on an outer surface thereof.
 18. The method of preparing dental prostheses of claim 16 in which said rod has an axially extending groove in an outer surface thereof.
 19. The method of preparing dental prostheses of claim 15 wherein said pin has a pair of wings on opposite sides of said pin.
 20. The method of preparing dental prostheses of claim 15 wherein said pin has multiple wings spaced along and around the outer surface of said pin.
 21. The method of preparing dental prostheses of claim 20 wherein said wings comprise rods extending less that a full length of said pin.
 22. The method for making dental prostheses wherein said computer generated model is produced by the fabrication of a solid object by at least one additive method selected from the group consisting of stereolithography, laminated object manufacturing, solid freeform fabrication, and fused deposition modeling.
 23. The method for making dental prostheses as in claim 22 wherein said computer generated model is determined by computer CAD design.
 24. The method for making dental prostheses as in claim 22 wherein said computer generated model is determined by medical images.
 25. The method for making dental prostheses as in claim 24 wherein said medical images are selected from the group consisting of x-rays, sonograms, CT Scans, nuclear imaging and magnetic resonance MRI imaging.
 26. The method of forming a dental prostheses as in claim 15 wherein said surgical guide is thermally formed on a top of said implant location of the model engaging the teeth or ridge surface with a close fit for transferring the analog positions accurately.
 27. The method for forming a dental prostheses as in claim 15 wherein a computer generated surgical guides which fits onto the jaw model is used.
 28. The method for forming a dental prostheses as in claim 15 further comprising the step of bonding surgical sleeves at the appropriate angle at the analog location onto the surgical guide.
 29. The method of forming a dental prostheses as in claim 15 wherein the surgical guide is snapped off at least one of the respective teeth and the respective ridge surface of the jaw model and is transferred to the patient's mouth and snapped onto at least one of the respective actual teeth and the respective ridge surface, thereby providing accurate guides for drilling at least one hole for at least one actual implant, while at a remote lab, a respective tooth crown prosthesis is being fabricated using said at least one analog inserted in the jaw model.
 30. The method of making a dental prostheses as in claim 15 wherein said surgical guide comprises an assembly of: a surgical guide sleeve supported by a form-fitting cylinder support mount, a tube adapter to adjust the height of said guide sleeve above the analog, and a screw threaded through the three parts from the top to secure the said surgical guide assembly to said analog below.
 31. A method for pre-surgical planning for cranial and facial reconstruction comprising the steps of: a. preparing a computer generated skull model; b. determining a locational position for a surgical bone implant to repair missing bone in the cranium, install ear prostheses, and/or install nose prostheses; c. using the computer generated skull model and preparing a surgical guide with oversize holes in registration with analogs for the surgical bone implants to be inserted at the locational positions determined by a surgeon on the skull model; d. fitting said surgical guide atop each analog, and bonding said surgical guide to the skull model at a predetermined angle of the analog in the skull, and e. removing said surgical guide attached for accurate drilling during the surgical procedure for insertion of the implants onto the skull of patient.
 32. The method for pre-surgical planning for cranial and facial reconstruction as in claim 31 wherein said surgical guide comprises an assembly of: a surgical guide sleeve supported by a form-fitting cylinder support mount, a tube adapter to adjust the height of said guide sleeve above the analog, and a screw threaded through the three parts from the top to secure the said surgical guide assembly to said analog below.
 33. The method for pre-surgical planning for cranial and facial reconstruction as in claim 31 wherein said computer generated model is produced by the fabrication of a solid object by at least one additive method selected from the group consisting of stereolithography, laminated object manufacturing, solid freeform fabrication, and fused deposition modeling.
 34. The method for pre-surgical planning for cranial and facial reconstruction as in claim 31 wherein said computer generated model is determined by computer CAD design.
 35. The for pre-surgical planning for cranial and facial reconstruction as in claim 31 wherein said computer generated model is determined by medical images.
 36. The method for pre-surgical planning for cranial and facial reconstruction as in claim 35 wherein said medical images are selected from the group consisting of x-rays, sonograms, CT Scans, nuclear imaging and magnetic resonance MRI imaging. 